4o6  Ammoniacal  Compound  of  Glycyrrhizin.  {^"^dlZ'^n'""' 
does  not  appear  to  have  been  noticed  that  the  sweet  taste  is  not  devel- 
oped in  glycyrrhizin  except  when  its  solution  is  effected  in  alkalies. 
Dilute  solutions  of  potash  and  soda  determine  the  solution  of  glycyr- 
rhizin very  rapidly  ;  the  sweet  taste  being  quickly  developed,  whilst  the 
liquid  takes  a  bright-yellow  color.  If  the  solution  be  evaporated  in  a 
water-bath  it  yields  a  scaly,  translucid,  deep-orange  residue,  which  re- 
dissolves  rapidly  in  cold  water,  and  possesses  the  peculiar  sweet  taste 
of  licorice.  The  employment  of  potash  or  soda  is,  however,  attended 
by  several  disadvantages,  especially,  when  added  in  excess,  that  of 
altering  the  glycyrrhizin  and  communicating  to  it  a  kind  of  soapy  taste. 
Glycyrrhizin  does  not  exist  naturally  in  licorice  root  as  a  sodic  or 
potassic  compound.  The  saccharine  matter  contained  naturally  in 
the  root  is  the  result  of  a  compound  of  glycyrrhizin  with  ammonia. 
This  may  be  demonstrated  by  washing  some  previously-bruised  licor- 
ice root,  either  fresh  or  dry,  in  a  concentrated  solution  of  potash  or 
soda,  when  there  is  immediately  developed  a  rather  strong  ammoni- 
acal odor.  The  same  reaction  takes  place  with  a  pure  extract  obtained 
by  exhausting  the  root  in  cold  water  and  evaporating  in  a  water-bath. 
Glycyrrhizin  forms  with  ammonia  two  compounds,  one  with  excess 
of  alkali,  which  yields  a  deep-yellow  solution,  the  other  containing  half 
the  proportion  of  the  alkali  and  giving  an  amber  solution.  The  first 
compound  is  obtained  by  employing  an  excess  of  ammonia  to  dissolve 
the  glycyrrhizin  in  water.  The  resulting  deep-yellow  solution  evap- 
orated to  dryness,  either  at  the  ordinary  temperature  or  in  a  boiling- 
water  bath,  leaves  a  shining,  scaly,  friable,  non-hygroscopic  residue, 
which  is  of  a  yellowish  color  and  constitutes  the  second  ammoniacal 
compound  ;  it  re-dissolves  readily  in  water,  communicating  to  it  an 
amber  color.  The  addition  of  a  few  drops  of  ammonia  immediately 
turns  the  color  of  this  solution  a  deep-yellow.  The  aqueous  solution 
of  the  second  ammoniacal  compound  reproduces  very  exactly  the  char- 
acteristic taste  of  licorice  root. 
The  author  states  that  glycyrrhizin  in  these  two  compounds  plays 
the  part  of  a  true  acid,  and  that  the  compounds  are  true  salts,  which 
undergo  double  decomposition,  not  only  with  nearly  all  the  metallic 
salts,  but  also  with  the  salts  of  the  organic  alkaloids.  The  precipitates 
formed  contain  glycyrrhizin  in  combination  with  the  oxide  or  the  alka- 
loid. Glycyrrhizin,  or  glycyrrhizic  acid,  appears  to  be  an  acid  interme- 
diate in  its  principal  properties  between  tannic  acid  and  pectic  acid. 
The  yellow  combination  formed  by  excess  of  ammonia  is  the  basic 
